Voting began Saturday in Sierra Leone's presidential runoff, a ballot to choose the diamond-rich but impoverished West African nation's first new leader since U.N. peacekeepers withdrew two years ago. The poll takes place against the backdrop of a tense electoral campaign that saw rivals clash with fists and stones. Observers view the election as a chance to measure whether Sierra Leone, still recovering from a decade of war that ended in 2002, can truly stand on its own. Opposition leader Ernest Bai Koroma, 54, is running against Vice President Solomon Berewa, 69, of the ruling party.

Turnout appeared much lower than the first round Aug. 11, with small lines and uncrowded polling stations visible across the capital, Freetown. Voters who showed said others stayed home because they feared violence.

Outside a school in central Freetown, armed police and soldiers stood guard. Inside, electricity worker Baimba Dumbuya cast his ballot, saying: "I am voting today because I want change and development."

In the first round, Koroma won 44 percent of the vote, compared to 38 percent for Berewa. Both men fell short of the 55 percent needed to win. On Saturday, a simple majority will suffice to win.

Koroma's opposition All People's Congress party already has won a majority in the 112-seat parliament, taking 59 seats, compared with Berewa's Sierra Leone People's Party, which won 43 seats.

The election issues that have resonated loudest are corruption and unemployment.

Sierra Leone has struggled to rebuild since the war's end, and corruption within the current government is seen as a serious drag on economic growth. Transparency International ranks Sierra Leone one of the most corrupt nations the world, 148th out of 163 surveyed.

If Koroma wins, it will mean a return to power for Sierra Leone's opposition for the first time in 15 years. Koroma's party was ousted in a 1992 coup by led by military officers, a year after the rebel uprising began.

The rebel war was infamous for its brutality. Tens of thousands of civilians died during the decade-long conflict, which ended after U.N. and British forces beat back the Revolutionary United Front rebels who had abducted thousands of children into their ranks, raped countless women and hacked off the limbs of civilians they thought didn't support them.

U.N. peacekeepers once numbered 17,500, but the force withdrew in the final days of 2005, leaving security to a new, 9,500-strong police force and a new, 10,000-strong British-trained army.

Though no fatalities have been reported during campaigning, even low-level clashes are significant given the country's bloody past.

Police have fired tear gas to disperse rock-throwing, machete-wielding party rivals in Freetown and other cities, and authorities imposed a brief curfew in the diamond-mining town of Kono last week after clashes.

Party offices have been burned down in some places and, in one of the gravest incidents, mobs barricaded roads and hurled stones at Koroma's convoy as it traveled to the eastern district of Kailahun, forcing him to flee.

President Ahmed Tejan Kabbah, who was prevented by law from running for a third five-year term, threatened to declare a state of emergency if the violence was not brought under control. Last week, he brought Berewa and Koroma together for talks, getting both to reign in supporters to ensure the polling is peaceful.

About 2.6 million of the nation's 5 million people were registered to vote Saturday.

Sierra Leone has grappled with instability since a coup six years after independence from Britain in 1961.

Today, the country is ranked second to the last on the U.N. Human Development Index - 176 out of 177 nations. Advocacy groups say it suffers some of the worst corruption on earth, and though progress has been made to improve transparency in the diamond industry - whose gems helped fuel the conflict - millions of dollars' worth of stones are believed to be smuggled out of the country annually.